Objectives during this year include chemical modification studies of: The role of hybrids as an explanation of HbA participation in gel formation by mixing deoxy hemoglobins; The influence of acetylating HbS with aspirin on sickling and gelatin; Identification of sites of chemical modification; Cyanate reaction of a-chain and b-chain aminotermini separately and examination of the different effects on gelation and sickling; and The composition of A1c and influence of it and S1c on sickling and gelation.